emails stuck in out box

Suddenly I can't send emails using my pop3 account. I tried sending some pictures that are in my gallery to my home computer and after a half hour I checked and they are in the outbox.
The gmail and yahoo accounts seem to be working.
I use the pop3 account for everything and need it working.
Help please.

When I had my problem, I was using a app called No Lock. Someone suggested that I turn the app off. I did and since then I have not had the same problem,, at all.
Another person said that the app No lock would have no effect on my email problem one way or the other. But I can't argue with results.

Thanks for the reply, mfinn. Unfortunately I do not have the app you mention (no lock). My Outlook account has been synching properly, but I am unable to send messages from the phone itself. (all the sent messages from my PC appear in the "Sent" box, but the messages sent from my phone have been stuck in the Outbox since last week.)